The Future of Fuel Efficiency

At the end of August this year, the US Department of Transport's National Highway Traffic Safety Administration (NHTSA) and the US Environmental Protection Agency (EPA) announced new standards to significantly improve the fuel economy of cars and light trucks by 2025. Last week, we took a look at a range of recent engine technologies that car companies have been deploying in aid of better fuel efficiency today. But what about the cars of tomorrow, or next week? What do Detroit, or Stuttgart, or Tokyo have waiting in the wings that will get to the Obama administration's target of 54.5 miles per gallon (mpg) by 2025?

The problem is historic

Ars tackles the future of cars

"The road ahead" is just the second installment in the Ars' three-part series. Last week Jonathan Gitlin tackled innovation in engine design. Next week: alternative methods for manufacturers to create more efficient vehicles. Whatever the technology, it's going to involve gasoline for at least the foreseeable future in the US. Automotive history helps us understand why. Author and journalist LJK Setright told us "we need hardly worry about who invented the motor car." While there are several inventors to whom the first horseless carriages can be attributed, Setright had a point when drawing the starting line through 1885 and Karl Benz's gas-powered three-wheeled machine. Victorian and Edwardian car makers drew on a wide range of fuels and engines. If a man in the street then predicted the next century, it wouldn't have been unreasonable to expect a diverse vehicular landscape. Back then, electric cars were marketed to women as they neither gave off clouds of exhaust nor required someone strong to crank the engine over (the invention of the electric starter motor finished this feature off). By 1900, Thomas Edison was ready to pick this technology as the winner.

Electricity might be making a comeback now, but it was the internal combustion engine—powered either by gas or diesel—that made automobile what it is. Unlike steam, drivers didn't need to stop for heavy fuel to burn or to top up the water for their boilers. Back then, much like today, batteries didn't charge fast enough or contain enough energy to meet most of our needs. But liquid hydrocarbons are cheap and easy to extract, they have good energy density, and don't require high pressure containment. So for over a century, the infrastructure to support the gas-powered car built up across the globe.

Of course, burning hydrocarbons isn't problem-free. They are a finite resource, one we're pulling out of the ground much faster than it took to get down there in the first place. Many of the richest deposits are controlled by autocratic or otherwise unpleasant regimes, upon which another nation might not wish to depend. And then there's the waste problem: nitrogen compounds can cause respiratory disease; lead additives affect development; and the big one, carbon dioxide, drives climate change. Despite these issues, the depth of infrastructure to support the gasoline engine is such that, for the foreseeable future, alternatives like hydrogen or even electricity will remain very niche choices.

The MPG equation

The basics of today's engines may have been put together more than 130 years ago, but that hasn't stopped engineers and scientists from finding new ways to travel further on the same gallon. That benefits drivers who have to pay to fill up their tank, as well as to society at large. It's why governments are using differing approaches to increase fuel efficiency. In Europe, that's mainly via escalating gas taxes, but here in the US we have the Corporate Average Fuel Efficiency (CAFE) regulations.

CAFE was introduced following the oil crisis in 1979 resulting from the Iranian revolution. It started with a modest goal, a mere 18 mpg, something even the Ford Model T was capable of achieving. CAFE increased average fuel efficiency over a number of years, up to 27 mpg in the mid-1980s, but the 1990s saw both oil prices and the idea of the US government exercising regulatory power both drop like stones. There we languished, until rising oil prices and growing sentiment about the need to address climate change intervened (such are the difficulties of making anything happen in Washington, DC). It was actually the car companies that moved first this time around, sensing that parsimonious punters might respond well. DC followed, and in August 2012, the government published new CAFE regulations that will raise average fuel economy to 54.5 mpg by 2025—almost double what they were a mere two years ago (you can find an interesting infographic showing the last 100 years of fuel economy here.)

Now, it's important to note that what CAFE says is a 54.5 mpg car and what the EPA says is a 54.5 mpg car are not really the same thing. For one thing, CAFE standards apply to, and are calculated for, a company's entire product lineup based on a complicated formula. That isn't the same as the simulation of supposedly real-world driving conditions that the EPA uses. What's more, within that product lineup, cars with a smaller footprint (say, a Mini) are expected to get better mileage than larger vehicles (your trucks or SUVs). So, in 2025, a car with a footprint of 41 sq. ft or less will be expected to deliver 61 mpg under CAFE, but only 43 mpg according to the EPA. At the other end of the scale, a truck with a footprint greater than 75 sq. ft only needs a CAFE rating of 30 mpg, or a mere 23 mpg from the EPA. Suddenly it seems like we're not even asking that much!

EPA/NHTSA Fuel Economy standards plus proposals through 2022, based on their published mathematical formulas.

At this point, some of you might be thinking "there are plenty of fuel-efficient cars, but they're all small and on sale in Europe!" Euro car nerds are but a tiny minority within these great United States. Most car buyers, whether they're in Manhattan, New York, or McAllen, Texas, are not going to be lining up for VW Lupos or Renault Twingos—even if they can do 70 mpg. But that's a problem of taste—let's worry about the technology first!

How the magic may happen

The first technology to consider is start-stop. It's arguably a current technology, at least in Europe where I've been hard pressed to rent a car without it. In fact, you could even get a VW Golf equipped with an early system as far back as 1994, but they didn't sell well. Since this is a US-centric site and start-stop is only just beginning to arrive on US roads, it counts.

Start-stop is designed to save gas when it's being most wasted, which is when the engine is running but the car is stationary (i.e. in a traffic jam). Simply, when the car comes to a halt, the engine cuts out. When it's time to move another car length forward, the engine refires and the driver carries on their merry way. One reason for the prevalence of start-stop in European cars, and its late arrival on these shores, is the preference our continental cousins have for manual transmissions. That's because stopping the engine when the car is stationary is the easier part.

As we discussed in part one, car engines are made up of many components with inertia and momentum. This means they can be started quickly, but not instantaneously. It's not so much of a problem with a manual transmission, as selecting first gear from neutral refires the engine (in practice—I've found it's still horribly easy to stall when trying to get moving quickly). But companies like Ford found it wasn't quite that simple with automatic transmissions.

In order to keep the gearbox's hydraulic pressure up, Ford fitted an electric pump. Also, to minimize the delay between the driver wanting to dart into an opening in traffic and the car moving, the transmission is kept in gear instead of dropping to neutral at a stop. "We had to develop some unique control algorithms for the engine and transmission to overcome this obstacle and still ensure an extremely quick, smooth, and quiet restart," said Birgit Sorgenfrei, Ford’s Auto Start-Stop program manager.

And to prevent the nightmare scenario of cars stranded in traffic jams with dead batteries, the control software also monitors the electrical drain on the car (from AC, audio, headlights, etc.) and disables start-stop when necessary. While start-stop doesn't offer much in the way of benefit when it comes to the EPA's fuel efficiency calculations, in city driving, such a system should be able to realize a gas saving of up to 10 percent. Not too shabby, but still not 54.4 in the near-term. Where do engines go from here?

The automotive industry has come up with plenty of ways to increase the efficiency of existing engines. Unfortunately, to reduce fuel consumption and emissions to the low levels of future standards, we can’t just rely on incremental improvements—entirely new kinds of internal combustion engines need to be developed. Fortunately, the research and industrial community has known this for the past few decades. They've been hard at work coming up with these.

Before talking about the new engine concepts, first we’ll dig a little deeper into how traditional engine types work to understand their limitations.

"The construction and operation of the line was authorized by the Pacific Railroad Acts of 1862 and 1864 during the American Civil War. Congress supported it with 30-year U.S. government bonds and extensive land grants of government-owned land."

Kyle Niemeyer wroteYou make good points—I didn't mention TFSI, and that approach does seem to solve some of the GDI issues. When comparing GDI emissions to diesel, I was mainly referring to those that run lean (but burn stoichiometric, like diesel), so I was painting with a pretty broad brush.

There is a lot to talk about with GDI, enough to make an article itself probably—but I didn't want to focus so much on that, especially since the research focused on future engines is moving in the areas I talk about after that. It might be good to come back to GDI later though, and address all the complexities and different operating modes.

Actually, if we talk about DI for ottos with VW/Audi as the example, it's even easier.The FSI labeled engines in the Golf V, at least the later models, were slightly redone and don't run lean anymore. With that change, the NOx cc in the exhaust piping also vanished. The issues were all related just to the lean running modes, not the direct injection or the approach in general.TFSI is basically the later, non lean, FSI with a T added for the turbocharger. Those also do not run lean and the block and injection are the same as for the normal, not lean anymore, FSIs, except for slight changes like forged pistons, compression ratio, cooling channels and such.(In general, all the SI engines (FSI, TSI, TFSI) have DI, but FSI was used for both, the lean running and the not lean running version.)

So, hmm, yeah, the part about SIDI should be revised and it should be made clear that it talks specifically about lean running SIDI engines, which are a different bunch from what's common. Afaik no German manufacturer builds them anymore (and afaik no one else either) and the direct injection, that is now common, doesn't have any of the drawbacks they introduced. From Googling, it btw looks like the lean running FSIs were never available in the US. I'd presume because of the need for very low sulfur fuel.What only stroke me after writing my last post is, that the graphic showing the combustion depicts that of a lean running engine specifically also.

Quote:

However, it should be noted that direct injection has the same NOX and soot emissions problems as diesel engines, and can’t use the three-way catalytic converter efficiently for the same reasons.

In that form, even with the context surrounding it, this is basically plain wrong, even with the surrounding context.

The part about reducing throttling and pumping losses is also not a direct effect of DI, but made possible (or easier) by that.

If I can help you with anything regarding the DI, lean running etc stuff, I'd gladly do.

What only stroke me after writing my last post is, that the graphic showing the combustion depicts that of a lean running engine specifically also.

How so? Obviously the diesel image depicts a flame around the injection plume but that's a lean-burn case. The SI image appears fine to me. Near TDC you initiate a spark that propagates out into the premixed cylinder.

One point that I didn't see in the article nor in the comments is that the diesel injection does not occur only near TDC and that's fundamental to the difference between the Otto cycle and the Diesel cycle. The Otto cycle is approximated as a constant volume heat addition. If the piston is moving slowly enough the combustible mixture goes from cold and low pressure to hot and high pressure at nearly constant volume. However, the Diesel cycle (more properly the dual air cycle but let's ignore that) is approximated as having constant pressure heat addition. This is accomplished by continuing to inject fuel into the cylinder as the piston moves away. Whereas the increase in volume would ordinarily result in a drop in pressure the added energy from combustion wants to increase the pressure. So for a portion of the power stroke the combustion continues whereas for a SI engine at low RPM it's essentially done right at the start and the pressure drops through the power stroke.

This is not a detail that needed to be covered in the article. I just thought it would help some of the non-car enthusiasts better understand the difference between the two systems.

My bonus, unrelated point this round - last time I looked at cars here in the US of A, a stick shift only costs $1000 less than an automatic.

That's why they're so hard to find on auto sales lots, especially on luxury models or really anything prices higher than a compact economy car. Dealers hate base models because options have higher margin than base cars and the aggregate income per transaction is also higher, reducing some overhead costs.

Auto salesmen in the U.S. are convinced that anyone who will buy a manual transmission will also buy an automatic, but automatic customers are unwilling to buy manual. Under that logic, only automatic cars should be stocked. This is why you can find rows of MX-5 roadsters, of all things, with torque-converter automatic transmissions in the States.

But the overwhelming vast majority or our rail is of the slow speed type. Here in Louisville, many people talk about how nice it would be to have a high speed rail that could take us to Nashville, Cincy and Indy in a half hour. You would see the job markets merge, access to jobs in rural areas improve and in general see a large amount of growth in all 4 cities. But for some reason, high speed rails are off limits as much as drilling in Alaska is off limits.

I take high-speed rail all the time along the Boston to Washington, D.C. corridor. I don't know if rail capacity is limited between Kentucky, Indiana and Ohio, but when rail capacity must be rationed it's more efficient to use rail for freight and to offload passengers to buses, automobiles or aircraft.

If there were rail between the destinations you cite it probably wouldn't be very popular because it would be more expensive than you'd prefer and slower than you'd prefer, like Acela currently is, and passengers wouldn't automatically have a car available to them at the destination. Half of all passenger train journeys in the States start or end in New York City largely because many city residents don't own cars. This doesn't apply in Kentucky or California, where high speed rail couldn't possibly break-even economically under current conditions.

The electric car movement relies on legislation and tax credit. It seems likely that the 99% who don't benefit from such rules might wake up and say - how bout you use that 'tax credit' money to help me to go to school..

More importantly [CNG has] the support infrastructure end to end. Electric is still building theirs.

Virtually every standalone structure in the entire U.S. has electricity. Scarcely any have expensive high-pressure CNG compressors for filling automobiles. Honda only sells a limited number of GXes in the States, mostly to institutional users. Filling up at stations makes it easy to tax CNG as a motor-fuel, eliminating a significant part of the cost savings.

Demanding high-voltage, high-current fast chargers on every corner to make battery-electrics viable is a straw-man argument.

Really, the answer to the car at destination problem is solutions like Zipcar.

I've been a member in the past. Zipcar was economically attractive before they raised the per-hour price and with business-user discount, but prices are much higher now and without, especially on the weekends. In the city I see from their rate-card that base models start at $14 an hour and $125 a day. They didn't used to differentially-price cars, either, a few years ago when the daily rate was $60 maximum.

Public transportation and shared-car services are especially easy to advocate when the evangelist doesn't use them and has alternative choices that are cheaper and more convenient.

Hmm. Yeah, you have a point there. You can view it like this and that's totally fine.I'll hereby revise what I said above about the graphic. (Look at the end of the post to see how I saw it.)

TDC is top dead center, right?If so, yes. I hinted at the time injection starts in an earlier comment, but said nothing about what happens then.

If I may add something, not implying that what you said lacks anything, let's take a look at injection pressure and the problem of a homogeneous mixture.Otto DIs need way lower pressure for their injections for two reasons. One is that the gasoline has a lower viscosity and can be nebulized (atomized, sprayed?) more easily. The other is that gasoline DIs don't inject into the running combustion, but only before that. Diesels need 4 digit pressures in bar to push the diesel into the combustion chamber and do so with as fine droplets as possible. Ottos can start to pee into the chamber during the compression stroke and rely partly on the air movements to help them nebulize the fuel. When the ignition happens, the mixture is readily built and injection is not happening anymore.For the diesel it's obviously harder to provide a good mixture. When the combustion has begun, the fuel jet begins to burn immediately upon leaving the nozzle and before it is really spread out, which is depicted in the graphic in the article. The outer parts meet with too much air, which causes NOx emissions, the inner parts of the beam tend to have too little air, resulting in soot.

The lean burning ottos now inherit part of exactly this diesel problem. They need to inject very late, just before the ignition, because otherwise they'd have a rather evenly lean mixture. They want to formal a normal mixture only near the spark plug, though. But without being able to rely on time and air movement too much, there will still be rather big droplets left from the injection inside the normal zone to cause soot, while the entire area where it bounds to the pure air into the cylinder will cause NOx emissions. Practically you can't just have a hard, abrupt and distinct border between the normal zone and the surrounding air, but will have an area where the mixture is lean, which makes the NOx thing even worse.

If you look at the picture of the otto ignition in the article now and assume the blueish part is the where the stoichiometric zone is, combustion in a lean burning otto DI looks like this, with the blue part being air-fuel mixture around the spark plug, the orange part being the border area with a lean mixture and the white area being the air.The other interpretation, like Wickwick said above, is also valid, where the image does not show an overview of the temporal dimension of the ignition, but a point in time just after ignition. The flame front travels like an expanding sphere from the spark plug outwards, and the picture could be showing what it is like in the combustion chamber in the middle of that journey.

@Hattori HANZO You're close to the mark on the GDI vs. Diesel discussion but let me add some detail.

The great thing about spark ignition engines is you do everything before the main event happens. Think way back before port fuel injection you had carburetors that sucked fuel in with the air compliments of the air pressure drop across the throttle. Port fuel injectors are immediately outside the intake port of the cylinders and spray onto the heated metal surface to vaporize the fuel. In 2000 I sat through a talk on the fuel injector technology used in Formula 1 race cars at the time - I don't know if they use DI now. They injected in the air intake snorkel a solid 4 cycles before the fuel reached the intake port (the massive acoustic waves formed from the opening of the values shatters the drops and was responsible for the secondary atomization required). Or we can shoot the fuel into the cylinder let it mix and evaporate. The goal is to create a combustible mixture.

So long as you're combustible (let's say from an equivalence ratio of 0.3 just for argument's sake) you don't need a stoichiometric zone anywhere. With a sufficiently powerful spark and enough turbulence to increase the flame propagation speed you can burn the mixture and don't necessarily have to reach the peak temperatures that a stoich flame would reach. Unfortunately, three-way catalysts really don't like oxygen so we don't want to run lean and we don't want to run rich and either exhaust unburned hydrocarbons (UHC) or burn them outside the cylinder so we don't want to run rich either.

The locally rich zone near the spark injector seems to me more like a stratified charge engine not a lean burn. There's no requirement for a Phi = 1 zone so long as your premixed cylinder is > Phi > 0.3 (about 130% excess air). However, to get to 200% or even 500% excess air a scheme as you describe might be necessary.

Now, on to injectors!

GDI injectors start injecting at the beginning of the compression stroke because they can. In fact, Diesels are starting (have been for years) to use multiple injections before the main event as well. It turns out that the biggest concern for GDI is wall wetting of the gasoline. Once the spray is fully-formed the droplets are generally small enough that the induced wrap-up-vortex in the cylinder will carry the drops away from the walls and will fill the entire volume with drop (the swirl of the intake and exhaust ports helps with this). However, on start any pulsed injector has a problem. At the beginning of the injection there is a slug of fluid that's not moving and has no pressure gradient to push it out the orifice. When the pressure ramps up on open this slug of fluid is accelerated slowly through this region and spits out into the cylinder. Worse, GDI injectors generally aren't limited to single- or multi-orifice atomizers. Many are pressure swirl. In such an injector if the liquid travels across the filming surface slowly it will not generate the instabilities necessary to rapidly break up.

In a Diesel spray the vast majority of the mass of fuel is carried in droplets < 8 micron in diameter. For GDI this number might be closer to 15 or 20 micron. However, the openings of a GDI or Diesel injector might be of the order of 50 - 150 micron. So, the blobs of fluid that spit out early in the injection are massive in comparison. These are likely to traverse the entire cylinder and impinge on the piston head or walls where they'll coke, create UHCs, CO, or other things we don't want. So the GDI avoids this by injecting early in the cycle while the piston is as far away as possible hoping that aerodynamics will break up these large blobs of fluid into smaller drops that will not impinge. Also, the goal is to fill the entire volume of the cylinder with vaporized fuel and air in as homogeneous a manner as possible. By injecting early the induced vortices, turbulence, and swirl have longer to mix things and evaporate the drops before the sprak arrives. Make no mistake. The GDI injection should be done lone before the spark comes along.

Diesel injectors have to inject beginning when the piston is nearly at top dead center. That doesn't give any travel for large blobs of fluid. Also, there's not a lot of flight time for drops to evaporate so they need to be as small as possible. That's why the rails on diesels are so high pressure not because of the differences in fuel characteristics. In the end everyone basically uses a variant of Stoddard Solvent to test injectors from port fuel injectors, GDI, Diesel or even for aircraft gas turbine engines.

There are other technologies that have been added to help diesels in addition to the massive pressure on their injectors such as multi-orifice geometries, multi-pulse patterns (where early spray droplets can mix and pre vaporize so the actual flame front does not have to sit at stoichiometric), and geometries on the injectors themselves that are designed to reduce these early large blobs (like larger sacks that actually create a film of fluid like a balloon that shatters into smaller drops faster than a single slug would).

My understanding is that US safety and emissions standards keep newer cars from being light enough to match the efficiency of older models.

It's a red herring to only blame the safety and emissions standards. They matter, but the consumer has demanded larger, more powerful cars as well. Even within model lines the cars have grown. For example, Accord used to be considered a compact, and has grown over the years where it is now classified in the mid-size range (or maybe it was mid-size and now it's standard, I forget exactly).

Oh, you have a valid point, individual models either get larger or get cancelled (ex: The larger Accord and the gone Tercel).

But that's not everything that's going on. A good example is the USA Smart ForTwo, or (in my personal case), a 2007 Accent. Currently-small model that I drive carefully and am lucky to get 30MPG out of (it's a Manual transmission BTW).

I wonder why even the smallest cars currently on the market can't match the efficiency of compact-to-midsize cars of the late 80's.

The fact that CAFE standards are somehow politically inflated over the real-world EPA mpg requirements does make it seem like it will be marginally easier to hit the 54mpg target, but don't be fooled - tweaking the engines of present day cars and trucks is not going to cut it.

It's an extreme example, but does illustrate a prevailing point - do you really need >200bhp to get to work in the morning ?

An more mundane example is the European 2012 Honda Jazz. It's knocking on 55mpg combined right now.

Yep, and that's exactly my point - we'll have to be driving much smaller, lower powered cars. If the politicians who are backing this goal would be honest about that, I'd have no problem - but they are pretending that this goal can be met without substantially changing the types of cars we drive.

I hope someone buys a Top Gear UK magazine from their local bookstore or supermarket, if they have one available. Look at the rear half, the bit that has car companies listed with bhp and mpg. There are many body styles that the US has but with engines not offered in the US. Fords, Toyotas, Nissans, even Chryslers and Jeeps. Heck, look at the Fiat 500. The US has probably the worst engine, mpg-wise, that they offer. They have options going up to 60 or 70 EU mpg? And we get the one that does 30?

Lotta this stuff never comes to the US because the car makers apparently think there's no market for it. I really hope this changes... I'd love a small fuel-efficient car and not have to pay some premium for a small fashion statement, it seems like these have become. Mini, Fiat, this stuff ain't cheap in the US. If I could use that as a daily driver and use my 5.7L V8 Charger on weekends or for trips, I'd love it. I'm taking the bus now for the 20 miles to get into work but would love to cut that down even further as I have to drive to a bus stop.

There's just no options for me that aren't stupid expensive. And even if I bought something in Europe, it doesn't look like I'd be allowed to drive it in the US if I had it shipped over.

These challenges notwithstanding, car manufacturers have built working HCCI engines—even road-worthy prototypes. GM developed a gasoline hybrid HCCI/spark ignition engine that operates in HCCI mode from idle to 60 miles per hour and at cruise, otherwise switching to spark ignition operation. This is necessary, because at higher speeds, the temperature in the cylinder increases, causing the mixture to ignite early and knock.

I wonder if an HCCI engine would work better if decoupled from the drivetrain and used instead as a generator for an electric vehicle like the Chevy Volt?

The HCCI engine could then be managed more easily by the engine computer as it could choose to run at a steady RPM, or could even be throttled back while the car is in use if an out of control situation like knock is sensed. Once the engine returns to control, generation could commence, with any gaps in generation filled by the vehicle battery.

Outstanding article/series by the way! I can infer from the number of comments that there are many gear-head tekkies out there.

Can someone clear up the whole US vs Europe thing? My understanding (from several years ago) is that there are various regulations that prevent many of the EU cars from just being brought to and run in the states.

I was cautioned against buying a German car and bringing it to the US because it would have required significant modification and cost.

Bullshit. The cars at Bathurst run at 75 L/100km, which is like 3.2 miles per gallon. (This is almost the same as F1 cars.)

The fuel is 50% bio-ethanol (significantly higher consumption than pre-bio-ethanol racecars), and they are running 100% throttle all more than half the time in a several hundred horsepower engine.

As far as I know that matches the full throttle on far less powerful engines running with higher energy density fuel.

Chuckstar wrote:

Ferrari may have experience making a car with exotic materials and a 1,000 hp engine slightly more fuel efficient. But that doesn't necessarily translate into making a passenger car with a 150 hp engine significantly more fuel efficient. And it definitely doesn't translate into making such a car cost-effectively.

Here I call bullshit on your claim. There absolutely would be things the passenger car industry can learn from it.

Chuckstar wrote:

I guarantee you, in addition, that Toyota spends an order of magnitude more on fuel efficiency R&D than Ferrari spends on all R&D in the entire company. Toyota spends about $9 billion a year on R&D.

How much of toyota's $9 billion dollars is spent on the visual appearance of the brake lights or comfort of the seats?

Toyota's massive R&D budget is not enough to make up for the fact they are working with a shoestring budget when it comes to actually building the engines. They spend, what, $900 on their engine?

I'm not saying we should all drive racecars. I'm just saying they care a lot more than we do about efficiently transforming fuel into movement and they have massive budgets for the actual engine parts and are working around the clock all year long engineering a more fuel efficient car. They are making new discoveries every day and we can learn from them.

Toyota, GM and VW probably each spend as much money on engine R&D in a year as the entire racing industry spends on its entire R&D budget. The major automakers simply have an order of magnitude more resources to put into such R&D.

Just look at all the new technologies you see in cars. 30 years ago and prior, there was a lot more transfer from racing R&D to production cars. But as the auto industry globalized, competition became more fierce and the R&D budgets of the major automakers ballooned compared to the racing teams. Also, as I indicated previously, it's a mistake to believe that every technology that debuted in racing was developed by or for the racing industry. Many technologies debut in racing simply because new technologies are expensive, and race cars have much higher budgets per unit than production cars. The example I gave above was carbon fiber. Another example is accelerate-by-wire, which debuted on F1, but was really just re-purposed aviation technology which was transferred into production models not long after the F1 debut. Accelerate-by-wire was coming to production cars with or without it's short solo act on the F1 circuit.

Honda has publicly stated that it's participation in F1 is a great training-ground for engineers, but provides virtually no technology transfer. In fact, in the interview I saw, they gave more examples of technology being transferred the other way. Production car technology that was not being used in F1, yet, until a Honda engineer said "hey, why don't we bring x or y from the Civic to the F1".

Let me give another example of the problem with race technology transfers. The KERS system in the Porsche 911 is descended from F1 KERS. But that model 911 is a half-million dollar supercar. KERS is nothing more than regenerative braking, which could be found in the Prius even before it debuted in F1. The F1 system uses a flywheel instead of a battery, but that is a much more expensive solution. That solution makes sense to F1 because flywheels can dump electrical energy to a motor much faster than batteries can. But batteries can move electricity plenty fast enough for the accelerations required by a production street car, and for much less money, and much more reliably over tens of thousands of street miles. The F1 KERS system is simply expensive overkill, unless you want 0-60 in under 4 seconds. The point is that race car engineers are developing solutions to different problems than production car engineers. And using dramatically fewer resources to do so. There's just very little that race car engineers develop that is applicable to production cars today, tomorrow or pretty much any time in the future.

Frankly, the important question isn't the average mix on the utility. The question is where the marginal electricity comes from when you add your car to the grid. For example, all of the nuclear generation on the grid gets used up already. So if you plug your car into the grid, you can't really say "it's OK, because part of the electricity comes from nuclear". The right question is "when you plug your car into the grid, where does the utility get the extra electricity from". In today's electricity generation market, that marginal electricity generally comes from natural gas.

And that is true for the two different types of marginal electricity you have to think about.

The first type of marginal electricity is the answer to the question "when I plug my car in to the grid at 6:00 pm today, which generating station increases its output in response". In most cases, the answer is natural gas.

But there's another way to look at marginal electricity, which is "if the utility expects to need 20MW more power next year, what kind of generation do they build". In that case, also, the answer is overwhelmingly natural gas in the U.S. market, with some renewables sprinkled around. Very little new coal, oil or nuclear is being added to the grid right now.

So it is probably reasonably valid (for the U.S. grid, at least), to treat the electricity usage of cars as coming from natural gas generation.

Can someone clear up the whole US vs Europe thing? My understanding (from several years ago) is that there are various regulations that prevent many of the EU cars from just being brought to and run in the states.

I was cautioned against buying a German car and bringing it to the US because it would have required significant modification and cost.

U.S. regulations do not allow for the same trade-offs between fuel economy and tailpipe emissions as EU regulations allow. So there are diesel engines allowed in Europe, for example, that sip fuel, but allow more particulates (or NOx, I'm not sure which) through the tailpipe than would be allowed in the U.S. The EU argument is that the lower fuel use more than makes up for the higher emissions per gallon of fuel. The U.S. argument is that we just don't want those emissions in the air. I don't know enough detail to have an opinion about which set of regulations truly result in cleaner air over a city. I'm kind of surprised if the EU system provides more flexibility to manufacturers to make trade-offs. Generally speaking EU industrial regulations have a greater tendency to be more rigid in making such tradeoffs compared to U.S. regulations, but that is certainly not a 100% observation.

Can someone clear up the whole US vs Europe thing? My understanding (from several years ago) is that there are various regulations that prevent many of the EU cars from just being brought to and run in the states.

I was cautioned against buying a German car and bringing it to the US because it would have required significant modification and cost.

Yes. Individual imports must meet EPA requirements and NHTSA crash standards based on their model year, and other requirements like theft-prevention. EPA exempts anything 25 years and older, and NHTSA doesn't care about those either.

When Paul Allen and Bill Gates imported a couple of rare Porsche 959s in the late 1980s, not long after regulations were tightened to inhibit grey-market imports, they found out they'd have to crash-test at least one 959 to get the model approved for road use. Once the crash tests are done, other importers can theoretically leverage the same crash tests, but the relevant agencies allow their red tape to make it hard for others to do that.

Several German automakers have a program where a buyer can take delivery of a car in Europe, drive it in Europe, then have it shipped to the U.S. as part of prearranged bulk shipments. Doing so saves taxes on one end or another, although the automakers have to let the American dealer take a percentage. These cars are all North American-spec models with temporary Europlates, and the programs are through the manufacturer. None of the German makes do anything very atrocious to international vehicle harmonization rules like use red turn-signals which is optionally allowed in North America (they must be amber everywhere else that cares).

There are some special regulations pertaining to the personal vehicles of military servicemembers stationed overseas, and temporary registrations for visitors, but they're not routes around the very strict U.S. regulations.

Another example is accelerate-by-wire, which debuted on F1, but was really just re-purposed aviation technology which was transferred into production models not long after the F1 debut. Accelerate-by-wire was coming to production cars with or without it's short solo act on the F1 circuit.

Better to call it throttle-by-wire, even without a throttle. Until the other accelerator pedal goes electric, anyway. I was really looking forward to mass availability of those Siemens VDO developed electric wedge brakes.

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Let me give another example of the problem with race technology transfers. The KERS system in the Porsche 911 is descended from F1 KERS. But that model 911 is a half-million dollar supercar. KERS is nothing more than regenerative braking, which could be found in the Prius even before it debuted in F1. The F1 system uses a flywheel instead of a battery, but that is a much more expensive solution.

The only 911 with KERS is a handbuilt race-car, to be clear. I once predicted here that flywheels would not be practical for street cars, if only because of the mass of the flywheel motor-generator, gyroscopic precession in a dynamic vehicle, and retained energy across prosaic road-driving timelines as opposed to the tight brake-corner-accelerate pattern of track use.

Frankly, the important question isn't the average mix on the utility. The question is where the marginal electricity comes from when you add your car to the grid. For example, all of the nuclear generation on the grid gets used up already. So if you plug your car into the grid, you can't really say "it's OK, because part of the electricity comes from nuclear". The right question is "when you plug your car into the grid, where does the utility get the extra electricity from". In today's electricity generation market, that marginal electricity generally comes from natural gas.

And that is true for the two different types of marginal electricity you have to think about.

The first type of marginal electricity is the answer to the question "when I plug my car in to the grid at 6:00 pm today, which generating station increases its output in response". In most cases, the answer is natural gas.

But there's another way to look at marginal electricity, which is "if the utility expects to need 20MW more power next year, what kind of generation do they build". In that case, also, the answer is overwhelmingly natural gas in the U.S. market, with some renewables sprinkled around. Very little new coal, oil or nuclear is being added to the grid right now.

So it is probably reasonably valid (for the U.S. grid, at least), to treat the electricity usage of cars as coming from natural gas generation.

There are also a lot of other benefits to using NG - most NG plants in the US are run during the daytime when power is needed. By also running them at night, they can get a higher utilization out of these facilities. This will spread their fixed costs for the plant ($1M/MW for NG) over more kWh generated and lower prices. They will have higher operational costs, but those should be factored into the price per kWh already, so selling more should have a neutral to positive effect on the financials.

You also have to factor in energy conservation/replacement as well. As people switch from incandescent to CFL or LED light, and cities switch to LED street lights, my car is "using" whatever that power saved was. As we become more energy efficient in our homes, EVs will negate (and then some) that energy savings from a generation standpoint. Which is a good thing, because it means that again, fixed costs per kWh sold stays the same and people's power rates wont actually go up.

Personally, my Volt is set to start charging at 10PM (when my utility's off-peak rates start) and finish around 2AM (240V/15A). Occasionally on the weekends I might charge during the day (but not in the summertime between 1-7P when I pay 33c/kWh).

The only 911 with KERS is a handbuilt race-car, to be clear. I once predicted here that flywheels would not be practical for street cars, if only because of the mass of the flywheel motor-generator, gyroscopic precession in a dynamic vehicle, and retained energy across prosaic road-driving timelines as opposed to the tight brake-corner-accelerate pattern of track use.

Porsche 911 GT3 R. Not street legal. I thought it was available for sale, but after Googling, it seems it was just an experimental version they've run at some endurance races. I probably got it mixed up with some other GT3 models, some of which are street legal and available for purchase. (I think some of the other non-street-legal versions can also be purchased for those collectors who buy track cars.)

There appear to have been rumors a while back that Porsche was going to add the KERS-flywheel as an option on the street-legal GT3s, but that was quickly rebutted by Porsche. Maybe that's where I got the wrong idea.

You also have to factor in energy conservation/replacement as well. As people switch from incandescent to CFL or LED light, and cities switch to LED street lights, my car is "using" whatever that power saved was. As we become more energy efficient in our homes, EVs will negate (and then some) that energy savings from a generation standpoint. Which is a good thing, because it means that again, fixed costs per kWh sold stays the same and people's power rates wont actually go up.

It's the same analysis for conservation. Which generator did they throttle down when someone switched from incandescent to CFL. That's the one that gets throttled back up when you plug in your hybrid. Typically, that marginal generation (again, at least on the U.S. grid) is natural gas. Coal, oil and nuclear are base load generators. They stay on the whole time, with natural gas turbines being turned on/off throughout the day. And most of the new generation added to the grid is natural gas.

It's not a perfect assumption, but treating grid energy as coming from natural gas co-gen will be reasonably accurate estimate when analyzing electric cars.

Better to call it throttle-by-wire, even without a throttle. Until the other accelerator pedal goes electric, anyway. I was really looking forward to mass availability of those Siemens VDO developed electric wedge brakes.

Fair enough. :-)

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I once predicted here that flywheels would not be practical for street cars, if only because of the mass of the flywheel motor-generator, gyroscopic precession in a dynamic vehicle, and retained energy across prosaic road-driving timelines as opposed to the tight brake-corner-accelerate pattern of track use.

I also meant to respond to this. Precession is not really a problem. You put the flywheel in gimbals. Getting power to/from a gimballed gyroscope was solved a half-century ago.

But a big issue on the experimental 911 with the flywheel, apparently, is that it is LOUD. Like really, distractingly, annoyingly loud. And not cool-loud, like a Ferrari engine. Just a loud turbine-like whining sound.

The electrical form of F1 KERS also required interesting ways to handle huge power dumps. I got involved in prototypes of a water-cooled resistor one system required (aluminum tube with resistor-over-insulator on the outside). But a hybrid, having a water-cooled engine, might still allow that part. I can just see more shade-tree mechanics getting electrocuted (or starting fires) by shorting large amounts of stored electricity.

I think a bigger issue is how we don't want our braking feel to be taken over so completely by energy recovery. I didn't like feel of earlier systems, where your braking pedal did not accurately modulate braking.

Back to the article coverage. The majority of the start-stop systems need high voltage to restart engines quickly, although there have been some clever workarounds (and also some that seem failure-prone). I haven't kept track of how many vehicles have gone to the 42-volt nominal (three times the current 12-volt nominal) electrical system. I know the GMT900-based hybrid truck used that voltage, but it seems like many hybrids are going straight to much higher traction voltages and keeping everything else at 12 with a traditional lead-acid battery, even though voltages higher than 50 volts incur safety implications and consequent compliance costs.

U.S. regulations do not allow for the same trade-offs between fuel economy and tailpipe emissions as EU regulations allow. So there are diesel engines allowed in Europe, for example, that sip fuel, but allow more particulates (or NOx, I'm not sure which) through the tailpipe than would be allowed in the U.S.

The US is harder on diesels. I think its sensible because CO2 is not carcogenic - and diesel particulates are. Natural gas burns even cleaner - then gasoline and is very abundant. Its the natural next gen fuel choice for the US but the electric car lobby is fighting it..

My solution would be to build tons of nuclear power plants and use heat electrolysis to generate relatively cheap hydrogen gas. Then you could use electric or hydrogen gas powered cars. But this won't fly because the same enviromentalists that push toxic batteries have "tv special' view of nuclear power..

Let me give another example of the problem with race technology transfers. The KERS system in the Porsche 911 is descended from F1 KERS. But that model 911 is a half-million dollar supercar. KERS is nothing more than regenerative braking, which could be found in the Prius even before it debuted in F1. The F1 system uses a flywheel instead of a battery, but that is a much more expensive solution. That solution makes sense to F1 because flywheels can dump electrical energy to a motor much faster than batteries can. But batteries can move electricity plenty fast enough for the accelerations required by a production street car, and for much less money, and much more reliably over tens of thousands of street miles. The F1 KERS system is simply expensive overkill, unless you want 0-60 in under 4 seconds. The point is that race car engineers are developing solutions to different problems than production car engineers. And using dramatically fewer resources to do so. There's just very little that race car engineers develop that is applicable to production cars today, tomorrow or pretty much any time in the future.

There are a few errors here. Firstly, the Porsche 911 variant with flywheel KERS isn't a production model, it's a racing version, and not a customer car like the 911 GT3 Cup or even the 911 GT3 RSR. And as far as I know, when the Porsche 918 Hybrid comes out in a year or two, although the pricetag is in the $700,000 range, it won't have flywheel KERS, but battery-based. Oh, and while technically the flywheel is F1-related, it was never actually fielded on an F1 car in anger (it was developed by Williams F1 but never raced).

Yes, you're absolutely right to demand more precision. What I described was in fact stratified fuel injection.

In return for correcting me, I'll add to your posting again

The swirl you explicitly described is these days not just a side effect and it is not only generated by the static design of the intake system. Modern diesels and ottos use special swirl flaps. In a simplified schematic they are dis-centered throttle flaps that only shield part of the intake canal to cause turbulences and have the air entering the cylinder "with a twist".Some years ago I btw actually met a self proclaimed engine expert that wanted to tell me his diesel had a throttle valve. Damn that was fun (Not to say those don't exist, but he definitely had not one of those.)

Considering your mention of a very mild hybrid with capacitors: BMW played around with that. I think it was around 2005 when I, erm, had contact with a very heavy of their models equipped with that. The caps were as big as my lower thigh.

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M. Jones wroteBack to the article coverage. The majority of the start-stop systems need high voltage to restart engines quickly, although there have been some clever workarounds (and also some that seem failure-prone). I haven't kept track of how many vehicles have gone to the 42-volt nominal (three times the current 12-volt nominal) electrical system. I know the GMT900-based hybrid truck used that voltage, but it seems like many hybrids are going straight to much higher traction voltages and keeping everything else at 12 with a traditional lead-acid battery, even though voltages higher than 50 volts incur safety implications and consequent compliance costs.

Er, I doubt the start stop systems need more than 12V. They need a thermally more capable starter, but starting a warm engine is a joke compared to starting a cold one. Turn the crank once and you're done. Any references at hand for that claim?

The 42V electrical system (also the 48V counterpart) has not taken off yet, at least for non hybrids. I can't name a single production car using that. Also, it's thrice the nominal 14V the generators produce. The battery is rated at 12V, but to fully charge it you need close to 14V.Hybrids go to higher voltages because too high amperage is hard to handle. It costs a ton for copper, weighs more and limits design. They stay with 12V for everything else because that stuff is readily available, cheap and reliable.

[/quote]The real issue is that driving stick is not compatible with the way Americans drive, which is with a phone in one hand and a donut in the other.

(I learned on stick, but switched to automatic years later.)[/quote]

Hey now we're not all cops.

Really now if that's all you can do when you're driving lol you should just give it up. Drive a semi for a while and deal with their crappy qualcomm's that are HUGE. Want to pull over to deal with it well be my guest but a message every 30 seconds gets tiresome.2. Every person I know had the urge to bug me on my cell pretty much around the clock.3. Driving for everyone around me a habit all truckers get use to because people + 2000 lbs of steel = scary. "Well only scary if I'm in a car.." I could say I could care less with 80,000 lbs behind me and no I don't mean my ass which happens to make up only 79,000 lbs. "I drove for others because I'd never forgive myself if I ran someone over with a semi."4. Dealing with my GPS + my map.5. 18 gears which were only about 7 or 8 driving empty lol and yea there was no need for the clutch once you learned to shift by sound. "Works for a four wheeler as well."6. Eating jk I had plenty of time to stop.7. Dipping my Red Man. "Okay okay I made that one up."

You want to know why people prefer automatics? It's not because of "DOUGHNUTS" or cell phones it is because it's very convenient.

The goal seems quite a low hanging fruit considering that in Europa, many cars and not only very small ones are already in the 80 US mpg range.

In France, the governement launched an initiative to sponsor research (tax incentives) for 120 mpg in 10 years.

However to acheive that, one of the key points is the ancillaries present in the car, especially A/C. Modern cars can use up to 10% of their power ouput for other things than moving the car and moving the additional weight.

It's not as low as you think - 1.2 gallons is an imperial gallon and real world testing almost no car seems to get what the manufacturer claims. Look at "fuelly' sometime - and see that realistically most cars get like 20-30 mpg.. 54.5 is MUCH MUCH higher..

Put the number high enough and every single car will have to be 'electric' even though they get that electricity by means of natural gas. . Cafe is a mess.